The Museum of HP Calculators

# Moon Landing Simulation for the 12C

This program is by Richard Beal and is used here by permission.

This program is supplied without representation or warranty of any kind. Richard Beal and The Museum of HP Calculators therefore assume no responsibility and shall have no liability, consequential or otherwise, of any kind arising from the use of this program material or any part thereof.

## Overview

This is adapted from the program in the library for the HP-25.

It needed quite a lot of changes because the tests x<0 and x<y do not exist on the HP-12C, so x≤y must be used instead.

An enhancement is that the remaining fuel is flashed on the display.

The existing documentation is otherwise correct except that in step 3 it should say just R/S not f PRGM R/S, and step 7 should be removed.

## Listing

```01   42 4      f 4             4 digit display
02   45 0      RCL 0
03   26        EEX
04   4         4
05   10        ÷               Divide X by 10000
06   45 1      RCL 1
07   0         0
08   43 34     g x≤y           If 0≤V?
09   43,33 14  g GTO 14        →  V positive or zero
10   33        R↓              V negative
11   34        x⇔y               Add V and -X
12   30        -
13   43,33 16  g GTO 16        →
14   33        R↓              Add V and X
15   40        +
16   31        R/S             Display V.X and get burn
17   45 2      RCL 2           Fuel
18   34        x⇔y
19   43 34     g x≤y           If Burn≤Fuel?
20   43,33 22  g GTO 22        →  Yes, so OK
21   43,33 42  g GTO 42        →  No, so prepare for crash
22   44,30 2   STO - 2         Subtract burn from fuel
23   5         5
24   30        -
25   44 3      STO 3           Acceleration is burn-5
26   2         2
27   10        ÷
28   45 0      RCL 0
29   40        +
30   45 1      RCL 1
31   40        +
32   44 0      STO 0           Altitude X=X+V+A/2
33   0         0
34   43 34     g x≤y           If 0≤Altitude?
35   43,33 37  g GTO 37        →  Yes, so OK
36   43,33 53  g GTO 53        →  No, so crash
37   45 3      RCL 3
38   44,40 1   STO + 1         V=V+A
39   45 2      RCL 2           Display fuel remaining
40   43 31     g PSE
42   45 1      RCL 1           Show crash
43   36        ENTER
44   20        ×
45   45 0      RCL 0
46   1         1
47   0         0
48   20        ×
49   40        +
50   43 21     g √x            V=√(V×V+2gX)
51   16        CHS             Show crash as down
52   44 1      STO 1           V
53   45 1      RCL 1           Jump here if hit ground
54   42 0      f 0
55   43,33 0   g GTO 00        →  Stop
```